The present invention relates generally to ribbon feed mechanisms and, more particularly, to an improved ribbon feed mechanism having drive and idler roller assemblies, each of which uses a single roller rotatably mounted on a retainer support featuring stripping portions attached to the retainer support which strip an endless printing (inked) ribbon off the rollers. The ribbon is fan or randomly folded, or stacked in loops or folds inside a cassette, cartridge or container used for holding the ribbon to be used during computer printing, dot matrix printing, typewriter printing operations, or other printing operations.
In the past, ribbon feed mechanisms have been used to fold or stack a length of printing (inked) ribbon inside different cartridges or containers for the purpose of furnishing an endless length of ribbon which may be used for printing purposes. The ribbon is typically fed into a container or cartridge by the feed mechanism which causes the ribbon to fold or stack as loops inside the hollow container, leaves the container for printing, and then returns back inside the container, where it is once again folded or stacked.
A feed mechanism using rollers with teeth is disclosed in U.S. Pat. No. 4,534,667, issued to Bury on Aug. 13, 1985. Each drive and idler roller assembly used for the feed mechanism described in this patent uses two rollers. Ribbon stripping guides are shown attached to interior walls or webs of a cassette holding a plurality of ribbon folds. The guides are used to strip the ribbon from the rollers after it is fed into the cassette. U.S. Pat. No. 4,131,372, issued to Hengelhaupt on Dec. 26, 1978, describes an endless ribbon cassette used for typewriters. The cassette has a feed mechanism with knurled rollers and uses stripping fingers attached to the walls or webs of the cassette to prevent ribbon fed into the cassette from winding about the rollers. Stripping fingers formed as part of interior walls of a cassette are described in U.S. Pat. No. 4,351,619, issued to Duke, et al., on Sept. 28, 1982. The stripping fingers prevent a continuous ink ribbon fed into the cassette by a feed mechanism from wrapping around dual rubber rings or rollers attached to each roller assembly. Movable stripper rings are used for the ribbon stripping mechanism described in U.S. Pat. No. 4,213,716, issued to Carson, Jr. on July 22, 1980. Drive and idler wheels or rollers with meshing teeth are used in this patent to feed an inked ribbon into a cartridge. The movable rings move the ribbon away from the rollers. Dual rollers are used for each of the drive and idler roller assemblies. Finally, U.S. Pat. Nos. 3,989,132, issued to Carson, Jr. on Nov. 2, 1976; 4,568,209, issued to Zerillo on Feb. 4, 1986 (dot matrix printer); and 4,589,789, issued to Quick, et al., on May 20, 1986, disclose other ribbon feed mechanisms.
Other roller assemblies have been fabricated in the past which use a plurality of rollers for each one of the drive and idler assemblies. The rollers are typically attached to a shaft or axial-like member and rotate with the shaft. A plurality of finger strippers have been used with the rollers. The finger strippers are attached to a support mounted inside a cassette, cartridge or container. The strippers fit between the rollers and are used to strip from the rollers a printing ribbon being fed into the cassette, cartridge or container. However, such roller assemblies are expensive to fabricate and do not always grip a printing ribbon with sufficient clamping force to provide the pulling force needed for long ribbons.